1. Field of the Invention
Generally this invention relates to the field of anti-condensation devices for preventing the formation of steam, fog, or condensation on glass or a similar surface; specifically to a condensation-free mirror which is self supporting in a shower and is capable of being manually adjusted into different positions during use.
2. Prior Art
Some prior-art mirrors which prevent or remove steam, fog, condensation, or other vision-obscuring moisture in the shower use a blower or baffle system to pass warm air over a glass surface in order to accelerate the evaporation of any fog or steam which is formed on the surface of the glass. Such air systems are not efficient and take a relatively long period of time (minutes rather than seconds) to remove the condensation. Also the moisture usually is removed from one edge of the glass, rather than all at once.
Exhaust fans are becoming fairly standard items for bathrooms, and in some instances they are supplemented by a separate blower unit for directing heated air across the surface of a bathroom mirror, e.g., as shown in U.S. Pat. No. 4,037,079 to J. Armbruster (1977) for a bathroom mirror defogger. However users could still use a separate shower mirror since men can obtain a closer, more comfortable shave at the time their beards are softened by the steam and hot water of a shower, while women's skin treatments are best applied in a steamy environment, as well as in front of a mirror.
Resistance wires imbedded in a sheet of plexiglass have been used as an alternative to blowers, but such devices can be dangerous when used in the vicinity of water. Also, the need for electrical power to activate the resistance wires requires the use of batteries or the like.
Water-heated shower mirrors have been proposed, but these have been awkward to install, complicated and hence expensive, and unreliable in operation.
Anti-fogging mirrors have also been proposed, but these do not operate reliably and require repeated applications of chemical anti-fog coatings.
Some prior-art anti-fog mirrors are connected by a pipe to the showerhead. This pipe diverts a portion of the hot water normally flowing out of the showerhead to a plenum behind the mirror. The hot water in the plenum heats the mirror so as to prevent hot water vapor ("steam") in the shower from condensing on and fogging the mirror. The hot water then drips or flows out of one or more drain holes in the mirror housing to the shower floor and drain.
One difficulty with these mirrors results from the variations in water pressure encountered in different installations. If the pressure is relatively low, say 14,000 kilograms per square meter (ksm) (20 psi), as might be encountered on the top floor of a multi-story building, an area with low water pressure, or an installation many miles from the water pumping station, the quantity of water flowing to the mirror will be relatively low, but sufficient to keep the mirror hot enough to prevent it from fogging, so that the arrangement works satisfactorily.
However if the pressure is higher than this, an excess of water will flow through the mirror. As a result some hot water will be wasted and the amount of water flowing out of the showerhead which is usable for bathing will be reduced more than necessary. This constitutes and economic as well as an ecological waste. It can become relatively great if the water pressure is high, say 53,000 ksm (75 psi) or more.
The problem can be solved when the mirror is used in a shower with high water pressure by making the pipe smaller. If the mirror is mechanically connected to the showerhead by a flexible arm, the lumen of the arm itself, or the lumen of an inner tube in the flexible arm can be made smaller. This will restrict the flow of watrer sufficiently so that only about enough water to defog the mirror will flow through the pipe or arm, thereby minimizing waste of hot water and allowing the maximum possible amount of water to be available for bathing. However this solution is not possible in a commercial manufacturing operation where no-fog shower mirrors are mass-produced for use in a variety of installations. If the lumen is made smaller and the mirror is installed in a shower with low water pressure, insufficient water will flow through the arm to to defog the mirror so that the system will be tantamount to useless.